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It's not just the '15w' designation that indicates the power of an amp. That just tells you what electrical power it consumes. The output of 'Loudness' comes out of the speaker in Decibels. It also depends on the output transformer & the speaker etc. Certain speakers have more efficiency than others. I'm sure the 'electrical' experts on this site would be able to explain it better than I can. For example, a Vox AC15 is nominally a 15w amp, but has several times more perceived volume than the 15w Superchamp.
The Celestion 'Blue' speaker helps a lot in that. I have heard great reports of the Fender Blues Junior. It has the EL84 output valves & a 12" speaker, so I guess will have a lot louder clean headroom than the Superchamp. David Martin used to use one, so I guess he's the guy to answer your question.

Tony.

RUSSET wrote:It's not just the '15w' designation that indicates the power of an amp. That just tells you what electrical power it consumes. The output of 'Loudness' comes out of the speaker in Decibels. It also depends on the output transformer & the speaker etc. Certain speakers have more efficiency than others. I'm sure the 'electrical' experts on this site would be able to explain it better than I can. For example, a Vox AC15 is nominally a 15w amp, but has several times more perceived volume than the 15w Superchamp.

It doesn't really depends on the output transformer, as the electrical power is measured after it, but it depends a lot on the speaker.

A speaker only convert a fraction of the electrical signal into sound. The efficiency of a speaker is measured in dB for 1W at 1m (theorically with a standarised baffle).
All speakers are not equal, the no name speakers found on budget guitar amps genarally have a 95 dB sensivity at best. The famous Celestion Blue has a 100 dB sensivty.

You need to double the electrical power to gain 3 dB, so a 15 W amp with a 100 dB speaker will be as loud as a 30 W amp with a 97 dB speaker.

So repacing the original speaker by a model with higher sensivity is an easy way to make an amp louder. The Eminence Ragin Cajun 10" speaker is rated at 100 dB, when the Fender Super Champ XD original speaker is certainly much lower (no figures are indicated, whichs says it all !).
As you can see on the photo I posteed earlier, both speakers use ceramic magnet, but the one on the Ragin Cajun is much bigger, which is needed to increase sensivity (alnico magnets are smaller for the same magnetic field, and neodimium even more so).
Among other 10" high sensivity speakers :

Eminence Red Fang 10 (alnico magnet) : 102 dB
Eminence Ramrod (ceramic magnet) : 100 dB
Jensen Neo 10-100 (neodimium magnet) : 98.9 dB
Celestion G10 Vintage (ceramic magnet) : 97 dB
Celestion G10 Gold (alnico magnet) : 98 dB

I have tested a Celestion G10 Vintage on a Vox Cambridge 30 amp, with great improvement over the original Bulldog speaker.

Of course you have to care also for tone, not all speakers sound the same...

Didier

Hi , i also have a Super Champ XD , Jimbo [ old fart ] changed one of the valves for me, with one that he got from Watford valves , this has stopped the distortion ,and improved the tone a lot , i love this amp , the best one ive had , Ron

That's interesting Ron, do you know what valve was changed? Although I'm perfectly happy with the amp, I'd like to try the 'voicing' channel at a bit more volume without distortion.

Love to know what valve needs changing too! Be great to get a bit more clean volume.

Hi ,the 12AX7 was changed for a JAN 5751 if i remember correctley [ i am 65 ] regards Ron

Just been reading about using an eq pedal in front of the XD. Seems that it makes a good improvement (especially at the bass end).
Anybody tried this ?
Was wondering if it might have anything to do with the lack of a "mid" tone control on the amp ?

This is what I read (harmony central) :- "took a different route out of boredom one day, and am quite glad I did. I got my EQ pedal off my pedal board and used it on this amp. I scooped the mids making it look like a "V", with a touch more on the left side than the right. (100 and 200) I flattened the amp's treble and bass to 5. The tone difference was astonishing. When using an external EQ, I get the absolute deep, rich tones that I love about Fender tube amps. You can now play this side by side with my Blues Deluxe at reasonable volumes and not have it sound really weak."

Cheers

Dick

ps...........when I can find an eq pedal I'll try it out & let you know my results.

Try a Danelectro 'Fish 'N Chips' EQ pedal, Dick. They are not too expensive & work fine.

Tony.

Re Twangers post:

Contacted Watford valves today and they confirmed that replacing the 12AX7 with a JAN5751 will give more clean headroom.
Price is £20 plus post and VAT. ordered mine!